Spherical fused silica compositions for injection molded ceramic cores and methods of making parts using such compositions
A single crystal ceramic core composition has an inorganic portion and an organic portion. The inorganic portion makes up about 85% by weight of the total weight of the ceramic core composition, and the organic portion makes up about 15% by weight of the total weight of the ceramic core composition. The inorganic portion includes about 94 to 98% by weight spherical fused silica, and about 2 to 6% by weight zircon flour. The organic portion includes about 84 to 88% by weight binder, about 1 to 2% by weight dye, about 6 to 12% by weight surfactant, and about 1 to 5% by weight polymeric fiber.
1. A single crystal ceramic core composition, comprising:
an inorganic portion comprising about 85% by weight of the total weight of the ceramic core composition, the inorganic portion comprising:
about 94 to 98% by weight spherical fused silica; and
about 2 to 6% by weight zircon; and
an organic portion comprising about 15% by weight of the total weight of the ceramic core composition, the organic portion comprising:
about 84 to 88% by weight binder;
about 1 to 2% by weight dye;
about 6 to 12% by weight surfactant; and
about 1 to 5% by weight polymeric fiber.
2. The ceramic core composition of claim 1 , wherein:
the inorganic portion of the ceramic core composition comprises:
95 to 97% by weight spherical fused silica; and
3 to 5% by weight zircon; and
the organic portion of the ceramic core composition comprises:
86 to 87% by weight binder;
1.2 to 1.6% by weight dye;
8 to 10% by weight surfactant; and
2 to 4% by weight polymeric fiber.
3. The ceramic core composition of claim 2 , wherein the spherical fused silica comprises a plurality of particles, the plurality of particles having the following particle size distribution:
size of particle
% of particles
(in microns)
0-3
<1.16
0-1.5
1.16-1.64
0-1.8
1.64-2.31
1.4-2.4
2.31-3.27
1.6-2.6
3.27-4.62
2.0-3.0
4.62-6.54
2.9-3.9
6.54-9.25
4.4-5.4
9.25-13.08
6.6-7.6
13.08-18.50
9.2-10.2
18.50-26.16
12.7-13.7
26.16-37.0
16.9-17.9
37.0-52.33
16.7-17.7
52.33-74.0
9.6-10.6
74.0-104.7
3.9-4.9
104.7-148.0
1.4-2.4
148.0-209.3
1.4-2.4
209.3-296.0
0-2
>296.0.
4. The ceramic core composition of claim 1 , wherein the spherical fused silica comprises a plurality of particles, the plurality of particles having the following particle size distribution:
size of particle
% of particles
(in microns)
0-3
<1.16
0-1.5
1.16-1.64
0-1.8
1.64-2.31
1.4-2.4
2.31-3.27
1.6-2.6
3.27-4.62
2.0-3.0
4.62-6.54
2.9-3.9
6.54-9.25
4.4-5.4
9.25-13.08
6.6-7.6
13.08-18.50
9.2-10.2
18.50-26.16
12.7-13.7
26.16-37.0
16.9-17.9
37.0-52.33
16.7-17.7
52.33-74.0
9.6-10.6
74.0-104.7
3.9-4.9
104.7-148.0
1.4-2.4
148.0-209.3
1.4-2.4
209.3-296.0
0-2
>296.0.
5. The ceramic core composition of claim 4 , wherein the binder is a thermoplastic material.
6. The ceramic core composition of claim 5 , wherein the thermoplastic material is a paraffin-based wax.
7. The ceramic core composition of claim 5 , wherein the surfactant comprises sodium stearate, aluminum stearate, and oleic acid.
8. The ceramic core composition of claim 7 , wherein the polymeric fiber comprises rayon fiber.
9. The ceramic core composition of claim 1 , wherein the spherical fused silica comprises a plurality of particles, the plurality of particles having the following particle size distribution:
size of particle
% of particles
(in microns)
0-2.7
<1.16
0.9-1.1
1.16-1.64
1.2-1.4
1.64-2.31
1.8-2.0
2.31-3.27
2.0-2.2
3.27-4.62
2.4-2.6
4.62-6.54
3.3-3.5
6.54-9.25
4.8-5.0
9.25-13.08
7.0-7.2
13.08-18.50
9.6-9.8
18.50-26.16
13.1-13.3
26.16-37.0
17.3-17.5
37.0-52.33
17.1-17.3
52.33-74.0
10.0-10.2
74.0-104.7
4.3-4.5
104.7-148.0
1.8-2.0
148.0-209.3
1.8-2.0
209.3-296.0
0-1.3
>296.0.
10. The ceramic core composition of claim 1 , wherein the spherical fused silica comprises a plurality of particles, the plurality of particles having the following particle size distribution:
size of particle
% of particles
(in microns)
0
<1.16
1
1.16-1.64
1
1.64-2.31
2
2.31-3.27
2
3.27-4.62
3
4.62-6.54
3
6.54-9.25
5
9.25-13.08
7
13.08-18.50
10
18.50-26.16
13
26.16-37.0
17
37.0-52.33
17
52.33-74.0
10
74.0-104.7
4
104.7-148.0
2
148.0-209.3
2
209.3-296.0
0
>296.0.
11. A single crystal ceramic core composition, comprising:
an inorganic portion comprising about 85% by weight of the total weight of the ceramic core composition, the inorganic portion comprising:
about 94 to 98% by weight spherical fused silica; and
about 2 to 6% by weight zircon; and
an organic portion comprising about 15% by weight of the total weight of the ceramic core composition, the organic portion comprising:
about 84 to 88% by weight binder; and
about 12 to 16% by weight surfactant and dye.
12. The ceramic core composition of claim 11 , wherein the surfactant comprises 6 to 12% by weight of the organic portion.
13. The ceramic core composition of claim 12 , wherein the binder is a paraffin-based wax.
14. The ceramic core composition of claim 11 , wherein the spherical fused silica comprises 96% by weight of the inorganic portion, and wherein the balance of the weight of the inorganic portion is zircon.
15. The ceramic core composition of claim 14 , wherein the binder comprises 86.5% by weight of the organic portion, and wherein the balance of the weight of the organic portion is surfactant and dye.
16. The ceramic core composition of claim 11 , wherein the surfactant comprises sodium stearate, aluminum stearate, and a fatty acid.
17. The ceramic core composition of claim 11 , wherein the spherical fused silica comprises a plurality of particles, the plurality of particles having the following particle size distribution:
size of particle
% of particles
(in microns)
0-3
<1.16
0-1.5
1.16-1.64
0-1.8
1.64-2.31
1.4-2.4
2.31-3.27
1.6-2.6
3.27-4.62
2.0-3.0
4.62-6.54
2.9-3.9
6.54-9.25
4.4-5.4
9.25-13.08
6.6-7.6
13.08-18.50
9.2-10.2
18.50-26.16
12.7-13.7
26.16-37.0
16.9-17.9
37.0-52.33
16.7-17.7
52.33-74.0
9.6-10.6
74.0-104.7
3.9-4.9
104.7-148.0
1.4-2.4
148.0-209.3
1.4-2.4
209.3-296.0
0-2
>296.0.